State police and fire department investigators examine and document the remains of a house and still standing garage that was the scene of a gas explosion on Sunny Valley Road in New Milford. Photographed Friday, Aug. 31, 2012.

State police and fire department investigators examine and document the remains of a house and still standing garage that was the scene of a gas explosion on Sunny Valley Road in New Milford. Photographed

The chimney is about left standing following a house explosion at a Sunny Valley Road residence in New Milford Wednesday, Aug. 29, 2012.. Police have confirmed one person is dead and at least two more have been taken to area hospitals following a gas explosion.
Photo by John Pirro less

The chimney is about left standing following a house explosion at a Sunny Valley Road residence in New Milford Wednesday, Aug. 29, 2012.. Police have confirmed one person is dead and at least two more have been ... more

Photo: Contributed Photo

Image 6 of 22

The chimney is about left standing following a house explosion at a Sunny Valley Road residence in New Milford Wednesday, Aug. 29, 2012.. Police have confirmed one person is dead and at least two more have been taken to area hospitals following a gas explosion.
Photo by John Pirro less

The chimney is about left standing following a house explosion at a Sunny Valley Road residence in New Milford Wednesday, Aug. 29, 2012.. Police have confirmed one person is dead and at least two more have been ... more

Photo: Contributed Photo

Image 7 of 22

The chimney is about left standing following a house explosion at a Sunny Valley Road residence in New Milford Wednesday, Aug. 29, 2012.. Police have confirmed one person is dead and at least two more have been taken to area hospitals following a gas explosion.
Courtesy of @ponnypunani) less

The chimney is about left standing following a house explosion at a Sunny Valley Road residence in New Milford Wednesday, Aug. 29, 2012.. Police have confirmed one person is dead and at least two more have been ... more

State police and fire department investigators examine and document the remains of a house that was destroyed by a gas explosion on Sunny Valley Road in New Milford. Photographed Friday, Aug. 31, 2012.

State police and fire department investigators examine and document the remains of a house that was destroyed by a gas explosion on Sunny Valley Road in New Milford. Photographed Friday, Aug. 31, 2012.

Holly Carlson, left, holds her children, Kodie, left, and Kaitlynn, as Karen McBride holds her daughter, Jocelyn, after joining the crowd in the singing of "Amazing Grace" during the Thursday, Aug. 30, 2012 vigil at John Pettibone School in New Milford for the victims in the home explosion that occured Wednesday, killing one and severely injuring two. less

Holly Carlson, left, holds her children, Kodie, left, and Kaitlynn, as Karen McBride holds her daughter, Jocelyn, after joining the crowd in the singing of "Amazing Grace" during the Thursday, Aug. 30, 2012 ... more

New Milford Conn. Assessor's Database photo
109 Sunny Valley Road in New Milford, Conn. Only the chimney remains from the home where an explosion Wednesday, Aug. 29, 2012 killed 47-year-old Anthony Fratino of New Milford, also critically injuring Fratino's nine-year-old son Nicholas and the owner of the home, 46-year-old John Wilkinson. less

New Milford Conn. Assessor's Database photo
109 Sunny Valley Road in New Milford, Conn. Only the chimney remains from the home where an explosion Wednesday, Aug. 29, 2012 killed 47-year-old Anthony Fratino ... more

Photo: Contributed Photo

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Rob Dempster, who lives in the Sunny Valley Road neighborhood in New Milford, shows his daughter Eleanor, 2, the scene of a house explosion Thursday, Aug. 30, 2012.

Rob Dempster, who lives in the Sunny Valley Road neighborhood in New Milford, shows his daughter Eleanor, 2, the scene of a house explosion Thursday, Aug. 30, 2012.

Photo: Carol Kaliff

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Investigators are at the scene Thursday, Aug. 30, 2012, of a propane explosion that leveled a home on Sunny Valley Road in New Milford Wednesday evening.

Investigators are at the scene Thursday, Aug. 30, 2012, of a propane explosion that leveled a home on Sunny Valley Road in New Milford Wednesday evening.

Photo: Carol Kaliff

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Investigators are at the scene Thursday, Aug. 30, 2012, of a propane explosion that leveled a home on Sunny Valley Road in New Milford Wednesday evening.

Investigators are at the scene Thursday, Aug. 30, 2012, of a propane explosion that leveled a home on Sunny Valley Road in New Milford Wednesday evening.

Photo: Carol Kaliff

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Investigators sift through the rubble of a home on Sunny Valley Road in New Milford Thursday, Aug. 30, 2012, that was leveled by the explosion of a propane explosion Wednesday evening.

Investigators sift through the rubble of a home on Sunny Valley Road in New Milford Thursday, Aug. 30, 2012, that was leveled by the explosion of a propane explosion Wednesday evening.

Photo: Carol Kaliff

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Police block off the Sunny Valley Road and Lane in New Milford Thursday morning where an explosion caused by a propane tank leveled a house Wednesday night, Aug. 29, 2012.

Police block off the Sunny Valley Road and Lane in New Milford Thursday morning where an explosion caused by a propane tank leveled a house Wednesday night, Aug. 29, 2012.

Photo: Carol Kaliff

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New Milford Police Officer Rob Tozzi blocks off the area on Sunny Valley Road in New Milford where an explosion leveled a house Wednesday evening.

New Milford Police Officer Rob Tozzi blocks off the area on Sunny Valley Road in New Milford where an explosion leveled a house Wednesday evening.

Photo: Carol Kaliff

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Debris from a home on Sunny Valley Road in New Milford, Conn., where an explosion Wednesday, Aug. 29, 2012 killed 47-year-old Anthony Fratino of New Milford, also critically injuring Fratino's nine-year-old son Nicholas and the owner of the home, 46-year-old John Wilkinson. Fratino and his son had come to help Wilkinson after Wilkinson arrived home to the smell of gas about 6:30 Wednesday evening. less

Debris from a home on Sunny Valley Road in New Milford, Conn., where an explosion Wednesday, Aug. 29, 2012 killed 47-year-old Anthony Fratino of New Milford, also critically injuring Fratino's nine-year-old son ... more

The results were released Tuesday from an investigation into the Aug. 29, 2012, explosion at Wilkinson's home.

The incident was determined to have been an accident and no criminal charges will be filed, State Police spokesman Lt. J. Paul Vance said.

Investigators found the explosion was the result of a liquid propane gas leak in the basement, according to the report.

Wilkinson and Fratino were investigating an odor of gas when an unidentified ignition source set off the catastrophic explosion that demolished the home, the report concluded.

The investigation was conducted by the New Milford fire marshal's office, the New Milford Police Department, the state fire marshal's office and the State Police's fire and explosion investigation unit.

Wilkinson said he had "no comment" Tuesday, adding he had not reviewed the final report on the investigation.

Fratino, 47, had come to the Sunny Valley Road home on Aug. 29, 2012, to help Wilkinson find the source of a propane gas odor. The explosion that leveled the house occurred moments after Wilkinson had called his neighbor to say it was safe to send his two young sons back home.

The boys had been sent to the neighbor's while they looked for the source of the odor. Wilkinson and Fratino's son, Nicholas, 8, were seriously injured in the blast.

Investigators found the gas leak was caused by an open, abandoned liquid propane gas line that had not been properly capped some nine years earlier when a gas dryer was removed

The line was inadvertently opened by contractors during installation of a gas hot-water heater and upgrading of the piping system, allowing the gas to flow freely into the basement area, the report stated.

"Anyone who switches gas appliances and works with a contractor must make sure when those changes are made any lines are permanently capped not just crimped or left wide open," said New Milford Fire Marshal Karen Facey.

"In this case, if that line had been capped, the results would have been much different," Facey said. "If you smell gas, get out of the house. Get a safe distance from the house and call 911. Let it go at that."